Compact Single-Port Harmonic Transponder for Backscattering Communications and Energy Harvesting Applications
Jinyao Zhang, Sumin David Joseph, Yi Huang, Jiafeng Zhou
Abstract
This article proposes a novel architecture for the design of a single-port harmonic transponder. The need for a diplexer is eliminated by adding a quarter-wave and a one-eighth-wave transmission line, combined with the two quarter-wave stubs that are usually needed in a conventional harmonic transponder. The proposed architecture provides isolation between the fundamental and the second harmonic signals and sends them to the desired port, while only introducing extremely low insertion loss. Compared with a single-resonator-based diplexer, it has a much wider bandwidth and a much more compact size than the conventional dual-port design. The proposed diplexing structure can also be used in the design of a compact single-port harmonic transponder with dc power supply capability. With such a design, the harmonic transponder can not only generate harmonics for communication purposes, but also provide power for the operation of communication modules, while being small in size and working with a single antenna. A harmonic tag with a simple modulation module based on this architecture is designed to demonstrate its practical value. The proposed design can work at a low input power level and is very suitable for future low-power Internet of Things (IoT) applications.